Abstract

FUTURE solar physics missions will require the ability to reposition multiple spacecraft at different azimuthal positions relative to the Earth, while remaining close to a one year circular orbit. Such azimuthal repositioningwill allow stereoscopicviews of solar features to be generated and will allow imaging of coronal mass ejections as they transit the sun-Earth line. The NASA STEREO mission, which is scheduled for launch in 2005, will utilize two spacecraft to perform such tasks. Both spacecraft will be launched on a Delta II 7925 and will use multiple lunar gravity assists to maneuver the spacecraft onto leading and trailing heliocentric orbits. The two spacecraft will then drift ahead of and behind the Earth on free-drift trajectories,with increasingEarth-sun-spacecraft angles.